5.7 is roughly 102 in US measurement which is a normal (slightly high normal really) . Low for you would be roughly under 3.8, maybe 3.3 depending on who you ask.

Are you on any medications? Certain ones increase your chances of low blood sugar, others don't. If you are not on medication then it is unlikely that you would need to worry about low blood sugar but it's always good to know the warning signs.